Immune Responses After COVID-19 Booster in Patients Recently Treated with Anti-CD20
Overview
This study evaluated humoral and cellular immune responses following a third mRNA COVID-19 vaccine dose in patients with hematologic diseases recently treated with anti-CD20 antibodies. While only 15% of patients showed humoral responses before the booster, this increased to 42% after vaccination, and T-cell responses were detected in 51% post-booster. Overall, 72% of patients exhibited either humoral or cellular immunity after the third dose.
Background
Patients receiving anti-CD20 monoclonal antibodies for hematologic diseases often have impaired antibody responses to COVID-19 vaccination, especially within 12 months of treatment. Although a third vaccine dose is recommended for immunocompromised individuals, seroconversion rates remain low when boosters are given shortly after anti-CD20 therapy. Cellular immunity may provide additional protection, but data on T-cell responses after a third dose in this population are limited. This study investigates immune responses after a longer interval between anti-CD20 therapy and booster vaccination.
Data Highlights
Parameter
Patients (n=53)
Healthy Controls (n=30)
Humoral Response Before Booster
15% (8/53)
100%
Humoral Response After Booster
42% (22/53)
100%
T-cell Response Before Booster
30% (16/53)
Not reported
T-cell Response After Booster
51% (27/53)
Not reported
Either Humoral or Cellular Response After Booster
72% (36/53)
Not reported
Median Interval from Last Anti-CD20 to Third Dose
311 days (IQR 250–386)
Not applicable
Median Interval Between Second and Third Dose
230 days (IQR 214–241)
Not applicable
Key Findings
Only 15% of patients had detectable anti-S1 IgG antibodies before the third vaccine dose, increasing to 42% after booster vaccination.
T-cell responses were present in 30% of patients before and 51% after the third dose, including many seronegative individuals.
Overall, 72% of patients demonstrated either humoral or cellular immune responses following the booster.
Shorter intervals between last anti-CD20 antibody administration and booster were associated with poorer humoral responses but did not affect T-cell response acquisition.
Use of bendamustine and lower IgM and B cell counts correlated with reduced humoral response.
Clinical Implications
Administering a COVID-19 booster vaccine at longer intervals after anti-CD20 antibody therapy may improve humoral immune responses in patients with hematologic diseases. Despite suboptimal antibody responses, many patients develop T-cell immunity, which may contribute to protection against severe COVID-19. Monitoring both humoral and cellular responses can guide vaccination strategies in this vulnerable population.
Conclusion
A third mRNA COVID-19 vaccine dose given at extended intervals post-anti-CD20 therapy enhances immune responses, with a substantial proportion of patients achieving humoral or cellular immunity. These findings support tailored booster timing to optimize protection in immunocompromised patients.
References
Centers for Disease Control and Prevention 2022 -- COVID-19 Vaccine Booster Recommendations
Previous Studies 2021-2022 -- Humoral Responses After COVID-19 Vaccination in Anti-CD20 Treated Patients
Study Authors 2022 -- Immune Responses Following COVID-19 Booster Vaccination in Patients Recently Administered Anti-CD20 Antibodies
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